One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,5)(4,6)(7,8)(9,10)(11,17)(12,15)(13,16)(14,19)(18,23)(20,22)(21,24)(25,26,29,33)(27,35,37,31)(28,32,40,45)(30,34,41,46)(36,47,49,42)(38,48,51,43)(39,44,52,54)(50,55,56,53)(1,3,4,7)(2,5,6,8)(9,11)(10,14)(12,18)(13,19)(15,21)(16,17)(20,24)(22,23)(27,36)(28,39)(30,41)(31,42)(32,44)(34,46)(35,47)(37,49)(38,51)(40,52)(43,48)(45,54)(2,6)(5,8)(9,12,13,20)(10,15,16,22)(11,18,19,24)(14,21,17,23)(25,27,30,36,29,37,41,49)(26,31,34,42,33,35,46,47)(28,38,39,50,40,51,52,56)(32,43,44,53,45,48,54,55)(10,16)(14,17)(15,22)(21,23)(27,37)(31,35)(36,49)(38,51)(42,47)(43,48)(50,56)(53,55) involution — undirected(11,19)(14,17)(18,24)(21,23)(25,28,30,39,29,40,41,52)(26,32,34,44,33,45,46,54)(27,38,36,50,37,51,49,56)(31,43,42,53,35,48,47,55)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.